<label for="dino-select">Choose a dinosaur:</label>
<select id="dino-select">
    <optgroup label="Theropods">
        <option>Tyrannosaurus</option>
        <option>Velociraptor</option>
        <option>Deinonychus</option>
    </optgroup>
    <optgroup label="Sauropods">
        <option>Diplodocus</option>
        <option>Saltasaurus</option>
        <option>Apatosaurus</option>
    </optgroup>
</select>
